The present application relates to a transfer sheet and a method for forming the transfer sheet, and particularly to a transfer sheet used when a transfer layer composed of an organic material is transferred to the device substrate side.
Organic electroluminescence (EL) devices that use electroluminescence achieved with an organic material include an organic layer formed by stacking an organic hole transporting layer and an organic light-emitting layer between a lower electrode and an upper electrode. Such organic electroluminescence devices have received attention as light-emitting devices capable of emitting high-intensity light with a low voltage direct current drive.
In recent years, compared with a mask deposition method or an ink jet method, a transfer method that can use a large substrate and considerably reduce manufacturing time has received attention as a technique for patterning an organic layer in the manufacturing of a full-color display using the organic EL devices. In the transfer method, a transfer sheet including an organic layer to be transferred is used. For example, a transfer sheet used in a thermal transfer method includes an organic layer on a substrate through a photothermal conversion layer.
In such a transfer sheet, the surface of the photothermal conversion layer that is a base surface where an organic layer is disposed is preferably clean and moisture, oxygen, or the like that decomposes the organic layer should not be adsorbed on the surface.
The adsorption of moisture or oxygen on the base surface of the organic layer is prevented by forming a silicon nitride film on the photothermal conversion layer and then by disposing an organic layer on the silicon nitride film.
Alternatively, it is proposed that a second metal layer including a metal such as aluminum (Al) or barium (Ba) that reacts with moisture or oxygen be coated on a first metal layer that is a photothermal conversion layer, and an organic layer be coated on the second metal layer. In this case, the second metal layer composed of a metal that reacts with moisture or oxygen is deposited on the first metal layer (photothermal conversion layer) by vapor deposition shortly before the organic layer is coated (refer to Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2008-500730, e.g., [0014]).